Bilateral Frontal Sinus Aplasia in Central Indian Adult Cadavers: Prevalence and Sex-Based Analysis

Background: The frontal sinus shows marked anatomical variability in size, shape, symmetry, and degree of pneumatization. Complete failure of pneumatization results in frontal sinus aplasia. Accurate recognition of this variation is relevant to endoscopic sinus surgery, anterior skull-base procedures, and forensic identification. Objective: To determine the prevalence of bilateral frontal sinus aplasia and examine its sex-based distribution in adult cadaveric specimens from Central India. Methods: This cross-sectional observational study examined 60 formalin-fixed adult cadaveric heads (36 male, 24 female) from an institutional anatomy collection in Central India. Each head was divided along the median sagittal plane and the frontal bone was inspected for pneumatization. When no midline cavity was seen, lateral osteotomies were extended approximately 2 cm superiorly and laterally along the supraorbital region to exclude a laterally positioned sinus. A rigid probe was used to confirm whether a mucosa-lined cavity communicated with the frontal recess. Fisher's exact test was used for the sex-based comparison, with p < 0.05 considered statistically significant. Results: Among 60 cadaveric specimens, bilateral frontal sinus aplasia was identified in 4 (6.67%; 95% CI: 1.8–16.2%). Unilateral absence was observed in 3 specimens (5.00%), while bilateral presence was noted in 53 (88.33%). Bilateral aplasia occurred in 2 of 24 female specimens (8.33%) and 2 of 36 male specimens (5.56%); the difference was not statistically significant (two-sided Fisher's exact test, p = 1.000). Conclusion: Bilateral frontal sinus aplasia, defined by gross anatomical absence after standardized dissection, was present in 6.67% of this Central Indian cadaveric series, without a statistically significant sex-based difference. Preoperative CT assessment remains important when frontal sinus or anterior skull-base intervention is planned. The findings should be interpreted in light of the convenience sample and absence of CT or surgical-outcome correlation.